Intermodulation between the various noise components affecting some power amps.
Different power amps have different topologies so will be affected to a greater or lesser extent.
Doesn’t help that a lot of high end amps pride themselves on simplicity and lack of phase shift, one way to approach those aims is to leave out some of the bits that filter ultrasonic noise (eg on the input stage to the power amp).
Mostly it’s fine but if you get a source that has a lot of ultrasonics and rf, and an amp that doesn’t filter ultrasonics and rf, and a particular power amp design that reacts badly to the particular mix of ultrasonics and rf, then it will be heard as hiss or hash in the audio band.
I could be wrong cos what do I know, but that is what I think has been going on ever since this was first mentioned.
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Disclaimer I do not own a ds mk2 or psa power amps.
I have seen and heard this problem (sometimes very obviously) with digital equipment and power amps a few times over the years, both guitar amps and hifi amps.
It is most annoying but easily addressable in firmware no doubt
Edit to add I guess a good way to test this hypothesis might be to insert a filter between the output of the ds and the input to the amps (which is what adding a preamp would be doing also) - a simple one stage RC filter might be a good starting point but note I am not suggesting this as a “fix” or even that a fix is needed, that’s just what my science project brain would suggest to confirm or deny this is what is going on.
Also of course if you don’t know what you are doing don’t try it, just wait for the next firmware
I reinstalled 228 Massive back in the DSD2 to do some experiments.
First, I disconnected the BHK 300s from the system.
I then hooked up a Fostex 6301B self powered mini monitor by way of an XLR cable.
The DSD output level was set to 35. The volume control on the Fostex was all the way up.
The extraneous noise was easily heard while music was playing.
I then gradually increased the level on the DSD while simultaneously decreasing the volume level on the Fostek monitor to maintain a constant listening level of the music.
The higher the volume control on the DSD was set to, the lower the volume of the noise became while the volume of the music remained constant.
When the volume of the DSD was at 100 and the Fostex mini monitor was set low to compensate for the volume of the music I do not hear any noise.
I am trying to install massive. But after highlighting the PPGA on the screen, when I press the middle button, nothing happens (nothing loads) and I go back to the regular screen. Why is it not loading?
I have been using a preamp since the Massive. I tested in my system as according to your method.
Usually I set the volume of DSD Mk2 fixed at “100” and adjust the volume of preamp during listening.
For testing I adjusted the volume of Mk2 at “50” and raised the volume at preamp. The result is consistent with your report. I could hear the intermodulattion noise which I had been thinking eliminated by inserting the preamp.
So, my earlier thought that preamp may be able to eliminate or suppress such noise is now turned out to be not correct. It seems more likely to be associated with attenuation inside DSD Mk2.
Thank you for your valuable survey.
Meanwhile, I find myself really love my current setup with the preamp (ML No.52) inserted in my system.
Before I insert the preamp, I liked the sound of DSD Mk2 directly connected to Hegel H30 operating as mono blocks. A few days ago I was just curious how it sounds if I connect the preamp to Luxman M-10X power amp. After switched from Hegel to Luxman, I surprised it sounds so much better than connected to DSD Mk2 directly previously. So much better as it even match with 2 Hegel H30s. I know there is synergy in audio since long before but this time the difference is striking.
I really love the sound of the combination with DSD Mk to ML No.52 to Luxman M-10X to FR20. (I even would like to add another M-10X for setup as mono blocks.)
Thanks for confirming the results of my experiment.
If anybody else wants to give it a try, I would suggest starting with the DSD at a level of 35. It is really bad at that volume.
Most of my listing is done at a level of around 50 but on a few recordings that are mastered at a really high level, I have to go down 35 or so.
A new twist to the intermodulation noise. I turned on my system today and with no music playing there was a 1Khz tone on top of the noise, checked with my Audio Tools RTA. I was on the optical input. The tone was still there as I cycled through all inputs until I got back to the optical input and the tone stopped, but the noise was still there. The intermodulation is always present not just on track transitions.
If you are asking me, my MKII was set at 46 which was my last listening setting. My MKII feeds a JL CR-1 crossover then directly to a pair of Benchmark AHB2 amps. I don’t use a preamp.
Thanks for mentioning.
I’ve asked because of prior mention on how to prevent the RF signaal from coming through when using a pre by setting the volume of the dac to (near) 100% .
If I assume the worst case senario that the Gon measurement is true, that means future MK2 upgrades will improve the sound even better than now. Maybe Ted is just sandbagging? LOL
I posted this there: Does this show that there is not a 1:1 correlation with SQ and noise measurements? JK starts with sound improvement is major (as do most here) but then says its measures worse than MKI. if true, then the measurements follower on a certain site might take notice.
What’s interesting is the top tier of stereo companies have stopped or never posted performance measurements except for the rudimentary ones. (power @ resistance, etc.)
When asked about possible poorer than expected measurements by commoners they will simply reply “then don’t buy it” or “we don’t listen to measurements or instruments”.
Seeing as everyone’s ear canal, room, and stereo rig are different your personal experience has to lead the way.
